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IC500 8051 Micro Controller's Main Functions:
There are 2 main functions of the IC500 8051 micro controller; signal switching and
standby controlls. IC500 communicates with ES80X6 microcontroller by using I
AUX1 signals)
Multiplexer (MUX) control signals for signal switching supplied by IC500. These MUX
signals are using the select signal sources and input-output signals.
MUX Control Signal list is shown in the following figure:
14.
CIRCUIT DESCRIPTION
14.1 POWER SUPPLY:
• Socket PL800 is the 220VAC input.
• 3.5A fuse F800 is used to protect the device against short circuit and
unexpected overloads.
• Line filter and capacitors L800, C800 and C803 are used to block the parasitic
coming from the mains. They also prevent the noise, produced in the circuit,
from being injected to the line.
• Voltage is rectified by using diodes D805 diode bridge. Using capacitor C815
(220µf) a DC voltage is produced. (310- 320VDC).
•
The current in the primary side of the transformer TR800 comes to the SMPS
IC (IC800 MC44608). The SMPS IC has a eight-pin DIP-8 package and an
external MOSFET with a cooler is mounted on it. It has a built-in oscillator,
overcurrent and overvoltage protection circuitry and runs at 100kHz. It starts
with the current from the primary side of the transformer and follows the
current from the feedback winding.
• Feedback current is deteceted by optocoupler IC803. Depending on the
control current coming from the secondary side, SMPS IC keeps the output
voltage constant by controlling the duty cycle of the ~30kHz signal (PWM) at
the primary side of the transformer.
19
2
C bus. (AUX0,
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